Disc brake and set of brake pads

ABSTRACT

A disc brake for a vehicle, in particular for a commercial vehicle, is provided. The disc brake includes at least one application-side brake pad and a back-side brake pad held in a form-fitting manner in a brake carrier. At least the application-side brake pad is provided with at least one pad-retaining spring which is supported at least on one brake carrier horn of the brake carrier and exerts a radially outwardly acting tensile force on the brake pad.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 14/939,748, filed Nov. 12, 2015, the disclosure of which is expressly incorporated by reference herein.

The present invention relates to a disc brake and to a set of brake pads for a disc brake, and in particular to brake pad retaining device arrangements.

Disc brakes of this type are used in particular in commercial vehicles and are frequently provided with pneumatic actuation. One embodiment of the brake caliper of disc brakes of this type is in the form of a sliding caliper and is used, for example, in a tight construction space in the vicinity of an adjacent wheel rim.

A sliding brake caliper is customarily connected to a supporting brake carrier via two bearing struts which are designed as fixed and movable bearings. The brake pads of the disc brake are guided displaceably in the brake carrier and are typically held in a spring-loaded manner in pad slots in the brake carrier by a pad-retaining clip.

In the case of disc brakes, in particular in the case of disc brakes with only one force introduction element, the design may induce an uneven wear of the brake pads. The brake pads may not wear in parallel either in the radial direction or in the circumferential direction with respect to a plane of the pad carrier plates thereof, which is referred to as radial or tangential wear.

An example of a spring-loaded pad-retaining clip is described in German Utility Patent No. DE 20 2008 013 446 U1.

The documents International Patent Publication No. WO 2013/143993 A1, German Patent Publication No. DE 10 2012 002 734 A1 and U.S. Pat. No. 8,540,061 B1 illustrate brake pad retaining systems.

Against the background of these solutions, there continues to be a constant requirement for an extended service life of brakes and brake components with a simultaneous reduction in costs.

The invention is therefore based on the object of providing an improved disc brake.

It is a further object to provide an improved set of brake pads for a disc brake.

The invention achieves the first object by providing a disc brake in which the application-side brake pad has at least one associated pad-retaining spring supported on at least one brake carrier horn a brake carrier and exerting a radially outwardly acting tensile force on the brake pad.

The further object is achieved by providing a set of brake pads for such a disc brake for a vehicle, in which the application-side brake pad has at least one pad-retaining spring with at least one pressure section that protrudes laterally over one end of the application-side brake pad's back plate.

Accordingly, a disc brake for a vehicle, in particular for a commercial vehicle, includes a brake disc with a brake disc rotational axis, at least one application-side brake pad and a back-side (also known as reaction-side) brake pad, a brake carrier which accommodates the at least two brake pads in a respective pad slot, wherein the at least one application-side brake pad is held in a form-fitting manner in the associated pad slot, and a brake caliper which straddles the brake disc and is designed as a sliding caliper. The application-side brake pad is provided with at least one pad-retaining spring which is supported at least on one brake carrier horn of the pad slot of the brake carrier and exerts a radially outwardly acting tensile force on the brake pad.

The radially outwardly acting tensile force makes it possible for the brake pad to be pulled into the form-fitting holder thereof, as a result of which a reduction in oblique wear is advantageously made possible.

The production of the tensile force is possible by an advantageously simple arrangement with at least one pad-retaining spring which is supported on a brake carrier horn of the pad slot after the brake pad has been fitted.

In one embodiment, the at least one application-side brake pad is in engagement in a form-fitting manner via a pad back plate with contours of brake carrier horns in the pad slot of the brake carrier. Fixing of the application-side brake pad in both radial directions with respect to the brake disc rotational axis is therefore advantageously made possible.

For this purpose, in a further embodiment, it is provided that the contours of the brake carrier horns correspond with contours of the pad back plate, wherein undercut surfaces of the contours of the brake carrier horns are in each case in engagement in a play-free manner with undercut surfaces of projections of the pad back plate.

In a further embodiment, the at least one pad-retaining spring is attached to the pad back plate. A compact brake pad is therefore created.

The at least one pad-retaining spring can be attached here on an upper side of the pad back plate, which permits a saving on space.

In yet another embodiment, the at least one pad-retaining spring comprises a central section; arms; pressure sections and transition sections, wherein the central section is attached on the upper side of the pad back plate, wherein the transition sections bear on the upper side of the pad back plate, and the pressure sections at one end in each case of the upper side of the pad back plate protrude laterally from the pad back plate. Effective and simple pretensioning of the pad-retaining spring can thus be produced. The pad-retaining spring can be, for example, a flat spring steel, from which said pad-retaining spring is produced as a punched and bent part.

In an alternative embodiment, the at least one pad-retaining spring comprises a central section; arms; pressure sections and intermediate sections, wherein the central section is attached by at least one fastening element to the pad back plate, wherein the pressure sections at one end in each case of the upper side of the pad back plate protrude laterally from the pad back plate. It is therefore made advantageously possible to use existing fastening elements without or only with minor amendments.

For this purpose, the at least one fastening element can be of clamp-like design and have a transverse section which, in the mounted state of the pad-retaining spring, extends through an opening in the pad back plate, wherein the pad-retaining spring is arranged between the at least one fastening element and an upper side of the pad back plate. This is advantageous since the pad-retaining spring is thereby attached captively to the pad back plate of the brake pad. A further advantage here is a clearance of the central part of the pad-retaining spring between the fastening element and the pad back plate, as a result of which uniform loading of the pad-retaining spring can be achieved.

In a further embodiment, the pad-retaining spring has at least one slit through which a section of the at least one fastening element extends. For example, existing punching tools can thus be used for slits of pad-retaining springs. In addition, it is possible for pad-retaining spring and fastening element to be kept captively together.

In yet another embodiment, the pad-retaining spring has at least one further slit through which a guide projection of the pad back plate extends. In this manner, the pad-retaining spring can advantageously be kept centered on the upper side of the pad back plate and can be guided in the possible longitudinal movements thereof in such a manner that a contact connection of the pressure sections with the brake carrier horns remains ensured.

If at least one of the pressure sections is supported on the at least one brake carrier horn of the pad slot of the brake carrier, an advantageously simple tensile force is produced on the brake pad, with no additional measures being required at the brake carrier.

In an alternative embodiment, the at least one pad-retaining spring is attached on an upper side of the pad back plate by at least one spring holder. An advantageous saving on weight is therefore made possible.

In a further embodiment, the at least one spring holder has at least one retaining element, wherein the at least one pad-retaining spring is arranged and held in a pretensioned manner between the at least one retaining element and the upper side of the pad back plate. This results in a simple production of pretensioning.

In yet another embodiment, the at least one pad-retaining spring comprises at least one central section, transition sections, at least one pressure section and at least one bearing section.

In a further embodiment, the at least one bearing section rests on the upper side of the pad back plate, and the at least one pressure section protrudes laterally from the pad back plate at an end of the upper side of the pad back plate. This results in an advantageously compact design.

For advantageously simple production of a tensile force which acts on the brake pad, the at least one pressure section is supported on the at least one brake carrier horn of the pad slot of the brake carrier.

In a further embodiment, the at least one retaining element is designed as a roller, in particular cable roller. A roller design of this type has the advantage of laterally guiding the pad-retaining spring.

In a preferred embodiment, it is provided that the at least one pad-retaining spring is produced from a spring wire. The pad-retaining spring is therefore simple to produce.

A further preferred embodiment provides two such pad-retaining springs at each end of the upper side of the pad back plate. This results in improved production of tensile force.

A set of brake pads for an above-described disc brake for a vehicle, in particular for a commercial vehicle, comprises the at least one application-side brake pad and at least one back-side brake pad. The application-side brake pad has at least one pad-retaining spring with at least one pressure section, wherein the at least one pressure section protrudes laterally over one end of an upper side of a pad back plate of the application-side brake pads.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a first embodiment of a disc brake according to the invention;

FIGS. 2-4 show partial views of a brake carrier of the disc brake according to the invention according to FIG. 1 with a brake pad according and embodiment of the invention;

FIGS. 5-7 show views of the brake carrier according to FIGS. 2-4;

FIGS. 8-9 show views of a second embodiment of the disc brake according to the invention;

FIGS. 10-11 show enlarged partial views of the second embodiment of the disc brake according to FIGS. 8-9;

FIGS. 12-13 show partial views of a third embodiment of the disc brake according to the invention;

FIG. 14 shows a perspective view of a pad back plate of a brake pad of the third embodiment according to FIGS. 12-13;

FIG. 15 shows a perspective view of a pad-retaining spring of the embodiment according to FIGS. 12-13;

FIG. 16 shows a perspective view of a fastening element of the pad-retaining spring according to FIG. 15;

FIGS. 17-18 show partial views of a fourth embodiment of the disc brake according to the invention;

FIG. 19 shows a perspective view of a pad back plate of a brake pad of the fourth embodiment;

FIG. 20 shows a perspective view of a pad-retaining spring of the embodiment according to FIGS. 17-18; and

FIGS. 21-22 show a perspective view and a cross-section elevation view, respectively, of a pad back plate of a brake pad and a pad-retaining spring of a fifth embodiment of the disc brake according to the invention.

Disc brakes of this type are used in particular in commercial vehicles and are frequently pneumatically-actuated. One embodiment of the brake caliper of disc brakes of this type is in the form of a sliding caliper and is used, for example, in a constricted construction space in the vicinity of an adjacent wheel rim.

Terms such as “top”, “bottom”, “right”, “left”, etc., relate to orientations and arrangements in the figures.

DETAILED DESCRIPTION

Disc brakes of this type are used in particular in commercial vehicles and are frequently pneumatically-actuated. One embodiment of the brake caliper of disc brakes of this type is in the form of a sliding caliper and is used, for example, in a constricted construction space in the vicinity of an adjacent wheel rim.

FIG. 1 shows a perspective view of a first embodiment of a disc brake 1 according to the invention, for example a pneumatic disc brake 1. FIGS. 2 to 4 illustrate partial views of a brake carrier 5 of the disc brake 1 according to the invention according to FIG. 1 with a brake pad 3 according to the invention. For the sake of better clarity, a brake disc 2 is not shown in FIG. 1, but is easily imaginable, for example as shown in FIG. 9. FIG. 2 shows a top view of a friction pad 3 b of the brake pad 3 in a brake carrier 5. FIG. 3 illustrates forces 11, 12 acting on the brake pad 3. FIG. 4 shows an enlarged illustration of one side of the brake pad 3 in engagement with a brake carrier horn 5′a.

The disc brake 1 is, for example, part of the brake system of a vehicle, in particular of a commercial vehicle, and comprises the brake disc 2 having a brake disc rotational axis 2 a, and two brake pads 3 which are arranged on both sides of the brake disc 2. Of the two brake pads 3, only an “application-side” brake pad 3 is shown here. The other “back-side” brake pad is easily imaginable, and may be identical to, or shaped differently from, the application-side brake pad. Furthermore, the disc brake 1 comprises the brake carrier 5, a brake caliper 6 and an application device (not shown).

The brake pad has a pad back plate 3 a, on which the friction pad 3 b is attached. The brake pads 3 are each accommodated in the brake carrier 5 in a pad slot 15, 16 (also see FIGS. 5, 6) between in each case two brake carrier horns 5 a, 5′a; 5 b, 5′b and are held in the brake carrier 5. A pad-retaining clip (not shown) is positioned above, i.e., radially outboard of, the brake pads 3. At least the brake pad 3 is guided displaceably in the direction of the brake disc rotational axis 2 a in the associated pad slot 15. During forward travel of the associated vehicle in a positive x direction, the brake disc 2 rotates about the brake disc rotational axis 2 a thereof in a main direction of rotation 10 (FIG. 3). That side of the brake caliper 6 which is located on the left of FIG. 1 is therefore referred to as the entry side and that side of the brake caliper 6 which is located on the right is referred to as the exit side. Accordingly, the brake carrier horns 5′a, 5′b are referred to as entry-side brake carrier horns 5′a, 5′b and the opposite brake carrier horns 5 a, 5 b are referred to as exit-side brake carrier horns 5 a, 5 b. Unless stated otherwise, components and assemblies which are assigned to the entry side are identified below by an apostrophe at the respective reference sign.

The brake caliper 6 is designed here as a sliding caliper and has an application section 6 a and a back section 6 b which are connected to each other at both ends in the direction of the brake disc rotational axis 2 a via connecting sections 6 c, 6′c. The application section 6 a and the back section 6 b are respectively arranged here on one side of the brake disc 2 in a manner parallel thereto, wherein the connecting sections 6 c extend in the y direction parallel to the brake disc rotational axis 2 a. The application section 6 a and the back section 6 b together with the connecting section 6 c form an opening over the brake disc 2 with the brake pads 3 for access thereto during installation, exchange and maintenance work.

The application section 6 a of the brake caliper 6 receives the application device of the disc brake 1. The application device serves for actuating the disc brake 1 and can have, for example, a pivoted brake lever with a compressed air cylinder. This is not described further here.

That side of the disc brake 1 on which the application section 6 a of the brake caliper 6 is arranged together with the application device is referred to below as the application side ZS. The other side of the disc brake 1, on which the back section 6 b of the brake caliper 6 is arranged, is referred to below as the back side RS, which is also called the reaction side. These terms “application side” and “back side” and other designations referring thereto are conventional and are used for better orientation.

The brake pad 3 with the pad back plate 3 a, which is located on the application side ZS, is thus referred to as the application-side brake pad 3, and the opposite brake pad to the latter is referred to in a corresponding manner as back-side brake pad.

The application-side brake pad 3 is acted upon by the application device during braking operations with an application force in the direction of the brake disc rotational axis 2 a. The back-side brake pad, which is not shown but is imaginable, is accommodated in the back section 6 b of the brake caliper 6 and, in the case of this disc brake 1 with the sliding brake caliper 6 does not have any movements relative to the back section 6 b.

The application-side brake pad 3 is provided with a pad-retaining spring 7 on an upper side 3 d of the pad back plate 3 a. The pad-retaining spring 7 (FIG. 2) comprises a central section 7 a; arms 7 b, 7′b; pressure sections 7 c, 7′c and transition sections 7 d, 7′d.

The central section 7 a is fastened to the upper side 3 d of the pad back plate 3 a approximately in the center of the upper side 3 d and extends to both sides in the longitudinal direction of the pad back plate 3 b (i.e. parallel to the brake disc 2 in the fitted state of the brake pad 3) in each case to a length which approximately corresponds to a quarter of a length of the pad back plate 3 d in the longitudinal direction. The fastening of the central section 7 a can take place, for example, by welding, rivets, screws and the like.

A respective transition section 7 d, 7′d via which a respective arm 7 b, 7′b is connected to the central section 7 a is attached to each end of the central section 7 a. The transition sections 7 d, 7′d are of curved design, wherein said transition sections are shaped convexly towards the upper side 3 d of the pad back plate 3 a. In this manner, the transition sections 7 d, 7′d each rest in linear contact on the upper side 3 d of the pad back plate 3 a. In this example, in the fitted state of the brake pad 3, the linear contact runs parallel to the brake disc rotational axis 2 a. Of course, other contact forms are also possible, for example single-point contact, multi-point contact, multiline contact, etc.

The convex transition section 7 d, 7′d span the central section 7 a, as a result of which said transition sections are pressed onto the upper side 3 d by means of the spring force of the central section 7 a.

Each transition sections 7 d, 7′d merges into a respective arm 7 b, 7′b. Each arm 7 b, 7′b extends as far as a respective end of the upper side 3 d of the pad back plate 3 a and rests with its respective end on the latter when the brake pad 3 is not fitted.

A respective pressure section 7 c, 7′c which protrudes in each case over the associated end of the upper side 3 d in the longitudinal direction of the pad back plate 3 a and is pressed onto the upper side 3 d of the pad back plate 3 a by the spring force of the central section 7 a, of the transition sections 7 d, 7′d and of the arms 7 b, 7′b is attached to each free end of an arm 7 b, 7′b.

Each pressure section 7 c, 7′c is of convex design in such a manner that the convex side thereof faces downwards towards the pad back plate 3 a. A rounding of the pressure sections 7 c, 7′c is smaller than a rounding of the transition sections 7 d, 7′d.

In this example, a width of the pad-retaining spring 7 is constant and corresponds here approximately to a thickness of the pad back plate 3 a. Width and thickness run in the direction of the brake disc rotational axis 2 a. Of course, the width of the pad-retaining spring 7 can also run differently with respect to the pad back plate 3 a or/and non-constantly.

The application-side pad slot 15 is delimited on both sides by the brake carrier horns 5 a, 5′a and in this embodiment is closed on the lower side thereof by a strut 5 d (the strut 5 d may be omitted). Each brake carrier horn 5 a, 5′a has, approximately in the center thereof in a direction perpendicular to the brake disc rotational axis 2 a, a respective lug 5 c, 5′c which protrudes inwards into the pad slot 15 and has rounded corners. An undercut 4, 4′ is formed below each lug 5 c, 5′c, said undercut being formed into the respective brake carrier horn 5 a, 5′a in each case outwards, i.e. starting from the pad slot 15 in a plane parallel to the brake disc 2, and in each case forming a contour with the lug 5 c, 5′c. Each undercut 4, 4′ runs below each lug 5 c, 5′c into the respective brake carrier horn 5 a, 5′a initially parallel to the strut 5 d. Said respective contour then runs in each case at a right angle in the brake carrier horn 5 a, 5′a downwards as far as a rest which, for its part, extends at a right angle towards the inner side of the pad slot 15 over a distance which approximately corresponds to the length of the undercut 4, 4′ below each lug 5 c, 5′c. Said rests are connected by the strut 5 d, wherein an upper side of the struts 5 d is arranged lower, i.e. further towards the brake disc rotational axis 2 a, than the surfaces of the rests. In alternative embodiments, the rests may be omitted if equivalent rest surfaces between the brake pad back plate 3 a and the lugs 5 c, 5 c′ are located at a higher location, for example, at flat surfaces machined into the top of the lugs 5 c, 5 c′ and into the back plate in the region directly above the machined flats.

Each side of the application-side pad back plate 3 a interacts with a respective brake carrier horn 5 a, 5′a and has a contour which corresponds to the respective contour of the associated brake carrier horn 5 a, 5′a. In other words, the shape of each lug 5 c, 5′c is formed into the associated side of the pad back plate 3 a, wherein a respective rectangular projection 3 c, 3′c of the pad back plate 3 a is formed, said projection corresponding with the respective associated undercut 4, 4′ of a brake carrier horn 5 a, 5′a. In this manner, the application-side brake pad 3 is accommodated by the pad back plate 3 a in the application-side pad slot 15 in the contours with the lug 5 c, 5′c and with the undercut 4, 4′ in a form-fitting manner such that the application-side brake pad 3 is guided displaceably in the direction of the brake disc rotational axis 2 a, but is fixed in the perpendicular direction to the brake disc rotational axis 2 a. Only the end regions of the lower side of the application-side pad back plate 3 a rest here on the respective rests at the ends of the strut 5 d.

In FIG. 2, the brake pad 3 is inserted into the pad slot 15 of the brake carrier 5. This takes place first of all by inserting the brake pad 3 radially into the intermediate space between the pad slots 15, 16 (FIGS. 5, 6).

In this embodiment, during installation the pad-retaining spring 7 is first of all supported on a brake carrier horn 5 a, 5′a. The brake pad 3 is thereby aligned to slide into the undercuts 4, 4′ of the brake carrier 5. Subsequently, the brake pad 3 is fixed in the pad slot 15 of the brake carrier 5 and can be pushed in the axial direction, i.e., in the direction of the brake disc rotational axis 2 a, into the working position thereof by the brake caliper 6.

The contours of the sides of the pad back plate 3 a of the brake pad 3 come into engagement here with the contours of the lugs 5 c, 5′c and of the undercuts 4, 4′ and form a form-fitting contact. The convex sides of the pressure sections 7 c, 7′c of the pad-retaining spring 7 are then in each case in contact by the contact sections 9, 9′ thereof for resting on rest sections 8, 8′ (FIG. 3) on the upper sides of the brake carrier horns 5 a, 5′. The pad-retaining spring 7 is supported here on the application-side brake carrier horns 5 a, 5′a and is tensioned upwards counter to the spring force of the pad-retaining spring 7.

The pad-retaining spring 7 which is tensioned on both sides in this manner exerts a tensile force on the brake pad 3 outwards in the radial direction in a manner pointing away from the brake disc rotational axis 2 a. This results in a play-free contact of the brake pad 3 against the brake carrier horns 5 c, 5′c by undercut surfaces 14, 14′ of the brake pad projections 3 c, 3′c on undercut surfaces 13, 13′ of the lower sides of the carrier horn lugs 5 c, 5′c.

In order to reduce tangential oblique wear (over the longitudinal side, i.e. the long side of the brake pad 3), in particular in the case of single-brake application spindle embodiments of the disc brake 1, a frictional force 11 is produced on the entry-side undercut surface 13′, 14′ by lever kinematics. The latter use a lever arm 11 a to generate a torque about a pivot point 10 a. The pivot point 10 a lies in contact here between an upper corner edge of the exit-side projection 3 c and a lower corner edge of the lug 5 c of the exit-side brake carrier horn 5 a between the undercut surfaces 13 and 14.

Said torque acts counter to an entering torque (force 12 with a lever arm 12 a—a known effect which allows the entering side of the friction pad 3 b to be worn more severely by support of the pad back plate 3 a of the brake pad 3 on the exit-side brake carrier horn 5 a) and therefore compensates for a part of the (tangential) oblique pad wear.

For optimum use of this effect, the undercut surfaces 13, 14; 13′, 14′ are designed in such a manner that they are in engagement in a play-free manner in the fitted state of the brake pad 3.

FIGS. 5 to 7 illustrate views of the brake carrier 5 according to FIGS. 2 to 4 of the disc brake 1 according to the invention according to FIG. 1.

FIG. 5 shows a perspective illustration of the brake carrier 5, as seen from the application side ZS (FIG. 1) looking at a fastening side 5 e of the brake carrier 5. The application-side pad slot 15 with the brake carrier horns 5 a, 5′a and the lugs 5 c, 5′c protruding into the pad slot 15 can clearly be seen. The back-side pad slot 16 has brake carrier horns 5 b, 5′b without lugs, which are connected by a strut 5 f parallel to the strut 5 d.

FIG. 6 illustrates the exit-side undercut 4 in enlarged form in a perspective view.

FIG. 7 shows an elevation view of the fastening side 5 e of the brake carrier 5. The brake carrier 5 is attached by the fastening side 5 e thereof to positionally fixed fastening sections of the vehicle.

FIGS. 8 and 9 show views of a second embodiment of the disc brake 1 according to the invention. A partial sectional view is illustrated in FIG. 8, wherein the section runs in a plane through the brake carrier 5 parallel to a brake disc plane. FIG. 9 shows a perspective view of the second embodiment of the disc brake 1. FIGS. 10 and 11 show enlarged partial views of the second embodiment of the disc brake 1 according to FIGS. 8 and 9.

In this second embodiment, the components of the disc brake 1 are identical to those in the first embodiment except for the brake pad 3. Therefore, only the differences of the brake pad 3 will be dealt with below.

The application-side brake pad 3 also has a pad back plate 3 a with a friction pad 3 b in this embodiment. The pad back plate 3 a is provided with contours which correspond with contours of the lugs 5 c, 5′c and undercuts 4, 4′. This has already been described above in conjunction with the first embodiment.

The pad back plate 3 a is formed in the side regions thereof on the upper side 3 d with a respective spring holder 17, 17′ for at least one pad-retaining spring 70, 70′ in each case. Each spring holder 17, 17′ comprises a projection 17 a, 17′a which protrudes upwards from the pad back plate 3 a. Each projection 17 a, 17′a is plate-like and protrudes upwards in approximately double the thickness of the pad back plate 3 a. An expansion of each projection 17 a, 17′a in the longitudinal direction of the pad back plate 3 a likewise corresponds approximately to double the thickness of the pad back plate 3 a. Each projection 17 a, 17′a is arranged offset at a distance from each side of the pad back plate 3 a toward the center thereof in the longitudinal direction thereof, wherein said distance approximately corresponds to the thickness of the pad back plate 3 a.

The back surface, which faces towards the application side ZS, of each projection 17 a, 17′a is aligned with the back surface of the pad back plate 3 a which faces towards the application side ZS.

A respective retaining element 18, 18′ is attached in the center of the side facing towards the friction pad 3 b of each projection 17 a, 17′a. In this embodiment, said retaining element 18, 18′ is a roller which is fixedly attached or is rotatable about an axis running parallel to the brake disc axis 2 a. Said roller can be designed, for example, as a cable roller. The upper side 3 d of the pad back plate 3 a is provided in the region below each retaining element 18, 18′ with a respective curved recess which corresponds with a roller diameter of the retaining element 18, 18′ and with respect to which each retaining element 18, 18′ is arranged at a distance.

A respective pad-retaining spring 70, 70′ is arranged between each retaining element 18, 18′ and the upper side 3 d of the pad back plate 3 a and is pretensioned by the shape thereof and the arrangement between each retaining element 18, 18′ and the respective recess of the upper side 3 d. Said pretensioning has the effect that each pad-retaining spring 70, 70′ rests with one end on the upper side 3 d of the pad back plate 3 a under pretension, wherein the other end protrudes over the respective end of the upper side 3 d in the longitudinal direction of the pad back plate 3 a and rests in a pretensioned manner on said end of the upper side 3 d when the brake pad 3 is not fitted.

Each pad-retaining spring 70, 70′ comprises a central section 70 a, transition sections 70 b and 70 c, at least one pressure section 71, 71′ and at least one bearing section 72, 72′.

The exit-side pad-retaining spring 70 is described below. The construction of the entry-side pad-retaining spring 70′ is of mirror-inverted design.

A transition section 70 b, 70 c is attached to each end of the central section 70 a. The transition section 70 b faces towards one end of the upper side 3 d of the pad back plate 3 a and connects the central section 70 a to the pressure section 71. The transition section 70 c is attached on the other side of the central section 70 a, faces towards the center of the upper side 3 d and connects the central section 70 a to the bearing section 72. Each transition section 70 b, 70 c is shaped with regard to the upper side 3 d in a manner curved towards the latter.

The lower side of the free end of the pressure section 71 has a contact section 9 which, in the fitted state of the brake pad 3, rests on the rest section 8 of the brake carrier horn 5 a. If the brake pad 3 is not fitted, the pressure section 71 rests on the end of the upper side 3 d of the pad back plate 3 a.

The lower side of the free end of the bearing section 72 has a rest section 72 a which rests continuously on the upper side 3 d of the pad back plate 3 a.

The central section 70 a is arranged between the retaining element 18 and a recess of the upper side 3 d of the pad back plate 3 a, wherein the central section 70 a does not make contact with the upper side 3 d. This is made possible by the recess and also by the configuration of the retaining element 18 in the form of a cable roller.

The transition sections 70 b, 70 c span the central section 70 a, as a result of which the pressure section 71 is pressed by the spring force of the central section 7 a either onto the end of the upper side 3 d or onto the brake carrier horn 5 a. At the same time, the central section 70 a which is tensioned in this manner has the effect that the bearing section 72 is also pressed onto the upper side 3 d.

In this example, the pad-retaining springs 70, 70′ are produced from a spring wire material. In this case, the ends are correspondingly bent over in order to form the pressure section 71, 71′ and the bearing section 72, 72′. Punctiform or/and curved contact sections are produced here in interaction with the respective rest surfaces.

The brake pad 3 is installed as described in the first embodiment.

FIGS. 12-13 show partial views of a third embodiment of the disc brake 1 according to the invention, wherein FIG. 12 shows a view of an actuation side 3 j of the pad back plate 3, as seen from the application side ZS (FIG. 1). FIG. 13 shows a view from the brake disc 2. FIG. 14 is a perspective view of a pad back plate 3 a of a brake pad 3 of the third embodiment according to FIGS. 12-13 onto the actuating side 3 j. FIG. 15 is a perspective view of a pad-retaining spring 7 of the embodiment according to FIGS. 12-13. FIG. 16 illustrates a perspective view of a fastening element 20 of the pad-retaining spring 7 according to FIG. 15 of the brake pad 3 of the exemplary embodiment according to FIGS. 12-13.

In this third embodiment, the components of the disc brake 1 are identical to those in the first embodiment except for the brake pad 3. Therefore, only the differences of the brake pad 3 are dealt with below.

The application-side brake pad 3 also has a pad back plate 3 a with a friction pad 3 b in this embodiment. The pad back plate 3 a is provided with the contours which are already described above and correspond with contours of the lugs 5 c, 5′c and undercuts 4, 4′.

In contrast to the first embodiment, the pad-retaining spring 7 is fastened in the center thereof to a fastening section 3 f by a fastening element 20. The fastening element 20 is described in more detail below.

In this third embodiment, the pad-retaining spring 7 includes a central section 7 a; arms 7 b, 7′b; pressure sections 7 c, 7′c and intermediate sections 7 e, 7′e.

The central section 7 a is provided with a slit 7 f running in the longitudinal direction of the pad-retaining spring 7 for receiving a section of the fastening element 20. The slit 7 f does not run in an imaginary central line of the pad-retaining spring 7, but rather runs offset in the direction towards the friction pad 3 b and parallel to the imaginary central line of the pad-retaining spring 7. Said imaginary central line runs in the longitudinal direction of the pad-retaining spring 7.

In contrast to the first embodiment, a length of the central section 7 a corresponds approximately to half the length of the central section 7 a of the pad-retaining spring 7 of the first embodiment.

A respective arm 7 b, 7′b is attached to each end of the central section 7 a. In contrast to the first embodiment, the arms 7 b, 7′b are substantially longer, for example in each case twice the length of the central section 7 a.

Each arm 7 b, 7′b is provided in the region of the free end thereof with a respective slit 7 g, 7′g. The slits 7 g, 7′g serve in each case for receiving a guide projection 3 g, 3′g on upper side 3 d of the pad back plate 3 a.

A respective pressure section 7 c, 7′c is attached to each free end of an arm 7 b, 7′b via an intermediate section 7 e, 7′e. Each intermediate section 7 e, 7′e is bent downwards in a manner facing towards the upper side 3 d of the back plate 3 a at an obtuse angle here from the respective arm end. To this end, each pressure section 7 c, 7′c is bent upwards in the opposite direction on a respective free end of an intermediate section 7 e, 7′e. The pressure sections 7 c, 7′c each extend laterally beyond the pad back plate 3 a and protrude from the latter at a distance which approximately corresponds to an expansion of a respective brake carrier horn 5 a, 5′a in the longitudinal direction of the pad back plate 3 a.

The fastening section 3 f protrudes from the upper side 3 d of the pad back plate 3 a and has a continuous opening 19 which runs through the pad back plate 3 a in the direction of the brake disc rotational axis 2 a. On that side of the pad back plate 3 a on which the friction pad 3 b is attached, the friction pad 3 b in the region of the opening 19 is recessed below and next to the latter, as can be seen in FIG. 13.

The fastening element 20 (see FIG. 16) is designed here in the manner of a clamp and comprises a plate 20 a, to the longitudinal sides of which respective trapezoidal side walls 20 b, 20 c are attached in each case approximately at a right angle. The trapezoidal side walls 20 b, 20 c run parallel and are connected at the short lower sides thereof by a transverse section 20 d. The transverse section 20 d is attached at a right angle to one side wall 20 b and is connected to the lower side of the other side wall 20 c at a connection 20 e, for example a weld seam. The transverse section 20 d runs parallel to the plate 20 a and, in the mounted state of the pad-retaining spring 7, extends through the opening 19. The connection 20 e is produced after the installation.

In the mounted state, the one trapezoidal side wall 20 b is guided through the slit 7 f running in the longitudinal direction of the pad-retaining spring 7. A wider longitudinal section of the central section 7 a of the pad-retaining spring 7 is arranged here between the side walls 20 b, 20 c and between the lower side of the plate 20 a and the upper side 3 d of the fastening section 3 f of the pad back plate 3 a with a certain play in the radial direction with respect to the brake disc rotational axis 2 a.

In the mounted state of the pad-retaining spring 7 on the upper side 3 d of the pad back plate 3 a, the guide projections 3 g, 3′g each extend through a slit 7 g, 7′g of the pad-retaining spring 7 and protrude from the upper side of each arm 7 b, 7′b. Contact sections 9, 9′ on the lower sides of the pressure sections 7 c, 7′c of the pad-retaining spring 7 are each in contact here with an associated rest section 8, 8′, as already described above.

In addition, in this embodiment, the pad back plate 3 a has upper bevelled corner sections 3 e, 3′e having a respective bevel 3 i, 3′i. Each bevel 3 i, 3′i merges via a recess 3 h, 3′h into a respective guide projection 3 g, 3′g and into the upper side 3 d of the pad back plate 3 a. The recesses 3 h, 3′h run from the respective bevel 3 i, 3′i initially in a rectilinear section which then has a respective rounded portion in the transition to the respective guide projection 3 g, 3′g and the upper side 3 d.

FIGS. 17-18 illustrate partial views of a fourth embodiment of the disc brake 1 according to the invention, wherein FIG. 17 shows a view of the actuation side 3 j of the pad back plate 3, as seen from the application side ZS (FIG. 1). FIG. 18 shows a view of the pad back plate 3 a without friction pad 3 b from the brake disc 2. FIG. 19 shows a perspective view of the pad back plate 3 a of the brake pad 3 of the fourth embodiment according to FIGS. 17-18, as seen from the side of the friction pad 3 b. The friction pad 3 b is not shown here, but is easily imaginable. FIG. 20 shows a perspective view of the pad-retaining spring 7 of the embodiment according to FIGS. 17-18.

In contrast to the third embodiment, the pad back plate 3 a does not have a fastening section 3 f with an opening 19, but rather an upper side 3 d which is continuous between the guide projections 3 g, 3′g. Two openings 19, 19′ which are each arranged in the vicinity of a guide projection 3 g, 3′g are provided in this fourth embodiment. A distance of said openings 19, 19′ from each other is smaller here than a distance of the guide projections 3 g, 3′g from each other.

In contrast to the third exemplary embodiment, the pad-retaining spring 7 of the fourth exemplary embodiment is in each case fastened in the end regions of the central section 7 a to the pad back plate 3 a by a fastening element 20, 20′. The fastening elements 20, 20′ are of identical design. A description in this regard has already been given above.

In this fourth embodiment, the pad-retaining spring 7 includes the central section 7 a; arms 7 b, 7′b; pressure sections 7 c, 7′c and intermediate sections 7 e, 7′e.

The central section 7 a is provided in the end regions thereof with a respective slit 7 f, 7′f running in the longitudinal direction of the pad-retaining spring 7 for receiving a section of a respective fastening element 20, 20′, as described above.

In contrast to the third embodiment, a length of the central section 7 a corresponds approximately to triple the length of the central section 7 a of the pad-retaining spring 7 of the third exemplary embodiment and is somewhat shorter than the distance between the guide projections 3 g, 3′g.

The arms 7 b, 7′b are respectively attached to each end of the central section 7 a. The arms 7 b, 7′b have a length which corresponds approximately to half the length of an arm 7 b, 7′b in the third embodiment.

Each arm 7 b, 7′b is provided in the region of the free end thereof with a respective slit 7 g, 7′g. The slits 7 g, 7′g each serve for receiving a guide projection 3 g, 3′g.

The pressure sections 7 c, 7′c are in each case attached to each free end of an arm 7 b, 7′b via an intermediate section 7 e, 7′e, as already described in conjunction with the third embodiment.

The pad-retaining spring 7 is attached to the pad back plate 3 a by the fastening elements 20, 20′ in such a manner that the central section 7 a runs at a substantially constant distance from the upper side 3 d of the pad back plate 3 a.

A set of brake pads has the at least one application-side brake pad 3 and at least one back-side brake pad. Said brake pads can also differ in length.

The invention is not restricted by the above-described exemplary embodiments, but rather can be modified within the scope of the attached claims.

For example, it is conceivable for the brake carrier 5 to be able to be realized with what is referred to as a radial groove 21 for simple installation of the brake pad 3. The groove 21 extends in the direction of the respective brake carrier horn 5 a, 5′a between one side of the associated lug 5 c, 5′c and an edge of the respective brake carrier horn 5 a, 5′a. This is illustrated in FIG. 6.

FIGS. 21-22 shown another embodiment which provides for maintaining a desired level of pad-retaining spring preload in highly spaced constrained environments. In the present invention, it is desirable to maintain a lifting force on the brake pads, in particular the inboard brake pad at all times following pad installation. For example, it may be desired to maintain a lifting force on the order of 200-250 N. In the event that this force must be maintained in a small available deflection range, for example 4 mm, a spring rate in the range of 50-65 N/mm would be required. However, a commercial disc brake of the type of the present invention may have an assembly tolerance on the order of 2 mm. Such a large tolerance could result in a pad-retaining spring having a 50-65 N/mm spring rate having a spring preload that could vary as much as 100-125 N, i.e., a variation that is greater than the 50 N tolerance of the desired 200-250 N preload range. Alternatively, if a pad-retaining spring with a lower spring rate were used, such as a 20 N/mm spring, the spring would have to deflect by between 10-12.5 mm to produce the desired 200-250 N lifting force. Such a deflection distance could not be tolerated in a space constrained environment.

FIG. 21 is a perspective view of an arrangement which can provide the desired brake pad lifting force in a space-constrained environment. In this embodiment, after the application-side brake pad 3 is initially installed in the brake carrier mount pad slot, the pad-retaining spring 7 is placed onto the upper surface 3 d of the application-side brake pad back plate 3 a, with pad-retaining spring slots 7 g, 7 g′ engaging back plate projections 3 g, 3 g′ and pad-retaining spring outer ends 7 c, 7 c′ resting on carrier mount horns 5 a, 5 a′. The pad-retaining spring 7 is then pressed radially inward toward the upper surface 3 d of the brake pad until a lift pin 75 can be inserted into an eye ring 3 k of the brake pad back plate 3 a that extends radially outward through an eye slit 7 h of the pad-retaining spring 7 (visible in the FIG. 22 cross-section elevation view). Once the lift pin 75 is installed, it may be secured in place, for example by a cotter pin 76. Preferably the force required to compress the pad-retaining spring 7 a distance sufficient to insert the lift pin 75 is equal to the desired lift force preload, in this example a compressive force of 200-250 N.

The act of pressing radially inward to compress the pad retaining spring 7 may be facilitated by use of the pad-retaining clip 10 as an installation tool. For example, in an embodiment in which the pad-retaining clip 10 is present an end of the clip may be partially inserted into a recess in the caliper application-side 6 a, then rotated downward onto the upper surface of the pad retaining spring 7. Due to the mechanical advantage provided by the length of the pad-retaining clip 10 as compared to the relatively short distance between the pad retaining spring 7 and the recess in the caliper application-side 6 a, the spring 7 may be compressed with relative ease to a point at which the lift pin 75 can be inserted with little or no insertion force. Once the pin 75 is installed, the pad-retaining clip 10 may be released as the pin 75 takes up the preloading force being applied to the spring. If the pad-retaining clip 10 is then to be installed on the disk brake, it may be removed from the recess in the caliper application-side 6 a and reoriented into the position in which it is installed when the brake is operable.

With this arrangement, the pad-retaining spring preload is established directly between the spring, the brake pad back plate and the mount horns, thereby substantially reducing or eliminating preload variations caused by assembly tolerance stack-up. This arrangement also permits use of pad-retaining springs with spring rates on the order of 20 N/mm, as the 10-12.5 mm of deflection required to establish a preload of 200-250 N may be accommodated during compression of the spring during brake pad installation, i.e., there is no need to be able to accommodate such large spring deflections during assembled brake operation. Further benefits of this spring preload arrangement include elimination of reliance on a retainer clip as a part of the brake pad lifting structure, although a retainer clip may still be present for other purposes, as shown in FIGS. 21 and 22. In these figures the retaining clip 10 is provided with a slot 10 b to accommodate the eye ring 3 k and lift pin 76.

Because such modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

LIST OF REFERENCE SIGNS

-   1 disc brake -   2 brake disc -   2 a brake disc rotational axis -   3 brake pad -   3 a pad back plate -   3 b friction pad -   3 c, 3′c projection -   3 d upper side -   3 e, 3′e corner section -   3 f fastening section -   3 g, 3′g guide projection -   3 h, 3′h recess -   3 i, 3′i bevel -   3 j actuation side -   3 k eye ring -   4, 4′ undercut -   5 brake carrier -   5 a, 5′a; 5 b, 5′b brake carrier horn -   5 c, 5′c lug -   5 d strut -   5 e fastening side -   5 f strut -   6 brake caliper -   6 a application section -   6 b reaction section -   6 c, 6′c connecting section -   7 pad-retaining spring -   7 a central section -   7 b, 7′b arm -   7 c, 7′c pressure section -   7 d, 7′d transition section -   7 e, 7′e intermediate section -   7 f, 7′f; 7 g, 7′g, h slit -   8, 8′ rest section -   9, 9′ contact section -   10 main direction of rotation -   10 a pivot point -   10 b slot -   11, 12 force -   11 a, 12 a lever arm -   13, 13′ undercut surface -   14, 14′ undercut surface -   15, 16 pad slot -   17, 17′ spring holder -   17 a projection -   18, 18′ retaining element -   19, 19′ opening -   20, 20′ fastening element -   20 a plate -   20 b, 20 c side wall -   20 d transverse section -   20 e connection -   21 groove -   70, 70′ pad-retaining spring -   70 a central section -   70 b, 70 c transition section -   71, 71′ pressure section -   72, 72′ bearing section -   72 a rest section -   75 lift pin -   76 cotter pin -   RS back side -   ZS application side 

What is claimed is:
 1. A disc brake for a vehicle, comprising: a brake disc having a brake disc rotational axis; a brake carrier configured to straddle the brake disc; an application-side brake pad and a back-side brake pad with respective back plates configured to be supported directly on the brake carrier in respective brake carrier pad slots; a brake caliper configured to straddle the brake disc while being supported on the brake carrier in a manner that enables sliding of the brake caliper relative to the brake carrier along a direction parallel to the brake disc rotational axis; at least one pad-retaining spring coupled to the application side brake pad, wherein the brake carrier and at least the application side brake pad have form-fitting complementary contours configured such that the form-fitting complementary contours directly abut one another when at least the application side brake pad is in an installed position in the brake carrier to constrain the application-side brake pad against radial movement away from the brake disc rotational axis, the at least one pad-retaining spring is configured to be supported at opposite ends directly on brake carrier horns adjacent to the application-side brake carrier pad slot and to exert a tensile force in a radially outward direction on the application-side brake pad, the form-fitting complementary contours include opposing brake carrier projections into the application-side brake carrier pad slot and complementary recesses in opposite lateral sides of the application-side brake pad, undercut surfaces of the contours of the brake carrier horns are configured to engage in a play-free manner undercut surfaces of projections of the pad back plate located radially inward of the brake pad recesses, the at least one pad-retaining spring is located on an upper side of the application-side brake pad back plate, the at least one pad-retaining spring includes a central section, arm sections adjacent to opposite ends of the central section, pressure sections adjacent to the arm sections, and intermediate sections between the central section and the adjacent arm sections, and the central section is attached to the application-side pad back plate by at least one fastening element and the pressure sections extend laterally beyond the lateral sides of the application-side brake pad back plate a distance sufficient to be supported on the brake carrier horns.
 2. The disc brake according to claim 1, wherein the at least one fastening element includes a transverse section extending through an opening in the application-side brake pad back plate and an upper section extending over the pad-retaining spring such that the pad-retaining spring passes between at least one fastening element and the upper side of the application-side brake pad back plate. 